Train-control system



Nov. 19, 1929. c. s. B-USHNELL TRAIN CONTROL SYSTEM Filed March 12, 1927 m, E V

Patented Nov. 19, 1929 unites STATES PATENT orricr:

CHARLES S. BUSHNELL, OF ROCHESTER, NEW YORK, ASSIG-NOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK TRAIN-CONTROL SYSTEM This invention relates in general to a train control system, and has more particular ref erence to an automatic inductive train control system of the alternating current type, including acknowledging and reset means.

In train control systems of the type re ferred to, it is usual to have spaced trackway inductors controlled in accordance with the tltlillC conditions and arranged to inductively influence a normally energized, alternating current, car-carried receiver, to cause such receiver to produce a train restricting influonce, such as a brake application, or the like, unless prevented by the proper operation of an acknowledging device. If the train restricting influence be exerted it is then generally necessary to manually operate a reset device to restore the various parts to normal. In such systems the car-carried device usually comprises a main relay with its energizing circuit tuned to oscillate most freely at the frequency of the current employed, so that after being de-ener 'ized, if its armature has assumed its retracted position, the energizing circuit is thereby detuned, and removal of the trackway influence does not permit reattraction of the armature of such relay, it being necessary, in some independent manner, to restore the armature to attracted position.

lVith the above and other considerations in mind, it is proposed, in accordance with this invention, to provide acknowledging and reset means for respectively preventing, for a temporary period, the drop away of the main relay armature, upon de-energization of such relay, and for restoring the dropped away a mature to its attracted position.

More specifically it is proposed in accordance with this invention, to associate with the main relay armature, an electromagnetically operated plunger arranged to move the main relay armature to attracted position and retain it in such position, when energized. Energization of the magnetic plunger is possible by means of an acknowledging device through a circuit including front contacts of the main relay, and through a reset device, accessible only when the car is at rest,

through a circuit independent of the main relay.

Further objects, purposes and characteristic features of the present invention will ap aear as the description progresses, reference being had to the accompanying drawing, showing, solely by way of illustration, and in a wholly diagrammatic manner, one physical form which the invention can assume.

The single figure of drawing shows one embodiment of the present invention, as applied to a train control system.

Referring to the drawing, there is shown a railway track comprising track rails 1, divided into signalled sections, in a usual mannor by insulating joints 2, each block being provided with a wayside signal 8 of the semaphore type, and an inductor l positioned along the side of the trackway adjacent the entrance end of each block. As indicated by dotted lines, the inductors are controlled by the signals to place them in active condition under caution and danger conditions of the particular block in question, and to place them in inactive condition under clear conditions of such block, the various control means and circuits, for the signals and for the inductor controls, not having been shown or described inasmuch as it is deemed non-c sential to a complete understanding of the present invention.

Carried on the car, represented diagrammatically by the wheels and axles 5, is a receiver core 6, of magnetic material, preferably laminated, having primary and secondary coils P and S, thereon, the primary coils being included in a circuit comprising a source of alternating current 7, preferably of higher than commercial frequency such, for example, as 860 cycles per second, and a condenser 8 so chosen as to tune the circuit in question to oscillate most freely at the frequency of the current employed. The secondary coils S are included in'a similarly tuned circuit including a condenser 9 and coils 10 carried on a core 11 of a main relay MR, the core 11 preferably being laminated to cut down losses due to eddy currents.

The main relay MR includes a pivot ed armature 12, biased to open position by a spring 1, and having contact fingers 1 1 and 15 electrically insulated from the body of the armature by insulating joints 16.

The organization includes a device EPV, arranged to cause an automatic brake appli cation, or a train movement restricting efifect of some character, and as shown in the drawing,it is an electro-pneumatic device, nor mally energized, and which, on de-energization, initiates the train restricting influence.

A reset contactor Res is shown and includes a rod 17 arranged to operate contact fingers 18 and 19.

iiin acl-mowledging device Ads is also included and comprises a spring biased depressible rod 20, arranged to operate contact fingers 21 and 22, the finger 21 moving with the rod, and the finger 22 being arranged, by means of a dash pot 23, and spring means 24-, to slowly open after operation of the rod 20, in a well known manner, the time constant in the particular case in question, being preterably about 15 seconds, whereby contact finger 22 does not break contact until about 15 seconds after operation of the rod 20.

The organization includes an acknowledging and reset means comprising a coil 25 having a movable plunger 26 arranged to move upwardly in the coil on energization thereof, and positioned adjacent the armature 12 of main relay MR so as to move such armature to attracted position, and retain it in such position, upon energization of the coil 25.

In order to simplify the wiring diagram, and the description, symbols B and C have been employed to indicate opposite poles of a source or sources of direct current energy, such for example as a storage battery, which, under certain circumstances, could obviously likewise indicatethe opposite instantaneous poles of an alternating current source of sup-v ply of electrical energy.

The various parts have been shown in the drawings in their normal conditions and positions, that is, with the train proceeding in clear territory.

The primary and secondary coils, P and S, on the receiver core 6, are inductively related so that the coils 10 of the main relay MR are normally energized by current induced in the secondary coils S, to thereby hold the armature 12 in picked up position.

The inductor and receiver are so related that the receiver passes over the inductor in inductive relation thereto, whereby, when the inductor is inactive, no appreciable efl'ect is produced on the receiver, and the various instrumentalities remain in the positions and conditions shown and described. Then the inductor however is in active condition, corre sponding to danger or caution trafiic conditions, the flux distribution in the receiver core 6 is so modified as to reduce the amount of current flowing through the secondary circuit including coils 10, to zero, or substantially zero, whereby to de-energize the main relay MR.

Assume, for the purpose of explanation, that the train is proceeding from a clear to a caution block, and that the engineman performs no act of acknowledgement when passing over the active inductor at the entrance to such block. In these circumstances the relay MR becomes de-energized, causing its armature 12 to drop away, thereby breaking the normal EPV energizing circuit, (traceable from one terminal C of any suitable source of energy, EPV, contact finger 19 and front point of Res, contact finger 22 and front point of Ada, contact finger 1 1 and front points of MB, to an opposite terminal B) at contact finger let and front contacts of relay ME, to thereby cause an automatic brake application.

The drop away of armature 12 of the main relay detunes the secondary circuit so that resumption of fiow of induced current in such secondary circuit is insufficient to restore the armature 12 and thereby re-energize EPV, to

releasethe brakes and allow the train to pro ceed, even though the secondary circuit were no taken through i ront contacts and contact linger 15 of the relay, making it a stick device which when once de-energized so remains until otherwise restored. With the relatively high frequency here employed, the detuning efi'ectdue to release of armature 12 has substantially the same effect as does the opening of a direct current circuit.

It is necessary, in order that the train can proceed, to operate the reset device Res which 1s positioned so as to be operable only when the train is at a full stop, due, for example, to positioning it to be accessible only from the ground. On depressing the reset rod 17, an energizing circuit for the coil 25 is completed, which can be traced from a source of energy 13, contact finger 18 and back contact of Res, coil 25, to G, to thus restore armature 12 to normal position, whereupon the secondary circuit including the coils 10 becomes again complete and also retuned and the armature is retained in attracted position by the normal flow of induced current through the secondary circuit, even though the reset device Res be restored to normal. In this connection it is necessary to restore the reset lever 19 to normal, since when in its operated position, its contact finger 19 and front contact, break the normal energizing circuit for EPV.

Under the conditions assumed, namely that the train was traveling from a clear to a caution block, if the engineer be alert,-and depress the acknowledging rod 20 a short time prior to passing the active inductor 1, an acknowledging energizing circuit is completed for the coil 25 which can be traced from a source C, coil 25, contact finger 21 and back contact of A070, contact finger 14 and front contacts of relay MR, to a source B. This acknowledging energization of the coil 2'5 causes the plunger 26 to move upwardly against the main relay armature 12 and hold it in its attracted position despite de-energization of the main relay coils 10. After passing the active inductor, the acknowledging rod can he released, and the normal current flowing in the secondary circuit including coils 10 retains the armature 12 in attracted position. In this manner an automatic brake application is avoided.

It should be noted that the slow opening contact finger 22 of Ada is included in the normal energizing circuit of EPV, such circuit including likewise the contact finger 19 and front contact of Res. Thus if the acknowledging device be tied down, or held down for too long a period of time, the energizing circuit for EPV is broken and an automatic brake application results. The inclusion of contact finger 19 of Res in the EPV normal energizing circuit, insures restoration to normal position of the reset device before the train can proceed.

It is of course quite clear that the acknowledging device cannot loe used to perform the function of the reset device since the energizing circuit for coil 25, controlled by A070, passes through the front contacts and contact finger 14 of the main relay, thus making the acknowledging device operative only when the main relay armature is in attracted position.

Ihe above described organization furnishes a properly safe guarded acknowledging and reset means for train control systems of the type in question, which functions in a wholly satisfactory manner and is quite simple in construction and operation.

he above rather specific description of one form of the invention, is shown solely by way of example, and is not intended, in any man- I nor whatsoever, in a limiting sense. Obviously, the invention can assume many different physical forms, and is susceptible of numerous modifications, and all such forms and modifications, are intended to be included by this application, as come within the appended claims.

Having described my invention, I now claim 1. In a train control system, a car-carried main relay having a normally energized circuit controlled in accordance with traffic conditions ahead, a brake applying device having an energizing circuit including a front contact of said relay and initiated when deenergized, a coil controlled plunger arranged when said coil is energized to place and maintain the armature of the main relay in attracted position, means for temporarily energizing the coil without breaking the energizing circuit of the brake applying device, and means for energizing the coil while simultaneously breaking the energizing circuit for the brake applying device.

2. In a train control system, a car-carried main relay having a normally energized tuned circuit controlled in accordance with traffic conditions ahead, a brake applying device having an energizing circuit including a front contact of said relay and initiated when de-energized, a coil controlled plunger arranged when said coil is energized to place and maintain the armature of the main relay in attracted position, means for only temporarily energizing the coil without breaking the energizing circuit of said brake applying device, and means for energizing the coil while simultaneously breaking the energizing circuitfor the brake applying device.

3. In a train control system, a car-carried main relay having normally energized tuned circuit controlled in accordance with trafic conditions ahead, a brake applying device having an energizing circuit including a front contact of said relay and initiated when cle-energized, an electrically controlled plunger having an energized and a de-energized position and arranged when in energized position to place and maintain the armature of the main relay in attracted posi tion, means for placing the plunger in energized position and simultaneously initiating operation of a slow opening contact in the energizing circuit of the brake applying de vice, and means for placing the plunger in energized position while simultaneously breaking the energizing circuit for the brake applying device.

t. In a train control system, a car-carried main relay having a normally energized circuit controlled in accordance with traffic con ditions ahead, a brake applying device having an energizing circuit including a front contact of said relay and initiated when deenergized, a coil controlled plunger, wholly separate from the main relay, arranged when said coil is energized to place and maintain the armature of the main relay in attracted position, means operable without affecting the energizing circuit of the brake applying device for energizing the coil, and means for energizing the coil while simultaneously breaking the energizing circuit for the brake applying device.

5. In a train control system, a main relay having a tuned energizing circuit controlled in accordance with traffic conditions ahead, a brake applying device having an energizing circuit including a front contact of the main relay and initiated when ole-energized, a coil operated plunger, a manually controlled acknowledging energizing circuit for the plunger coil, including a front contact of the relay, and a reset energizing circuit for the coil.

6. In a train control system, a main relay having a tuned energizing circuit controlled in accordance with trafiic conditions ahead, a brake applying device having an energizing circuit including a front contact of the main 5 relay and initiated when de-energized, a coil operated plunger, a manually controlled acknowledging energizing circuit for the plunger coil including a front contact of the relay, and a slow opening contact finger 19 in the energizing circuit for the brake applying device initiated upon closing of the acknowledging circuit, and a protected reset energizing circuit for the coil.

7. In a train control system, a main relay having a tuned energizing circuit controlled in accordance With trafiic conditions ahead, a brake applying device having an energizing circuit including a front contact of the main relay and initiated when deenergized, a di- 27) rect current coil operated plunger, a inanually controlled acknowledging energizing circuit for the plunger coil including a front contact of the relay, a slow opening contact finger in the energizing circuit for the brake applying device initiated upon closing of the acknowledging circuit, and a protectet reset energizing circuit for the coil.

In testimony whereof I afl'ix my signature.

CHARLES S. BUSHNELL. 

